Paper machine hood



March 4, 1958 F. w. HOOPER 2,825,430

PAPER MACHINE HOOD Filed July 13, 1953 8 Sheets-Sheet 1 llIll Hw" I |IIIHIIWIINHII" Il Hummm.. Mill! March 4, 1958 F. w. HOOPER 2,825,430

PAPER MACHINE Hoon Filed July 13. 1953 a sheets-sheet 2 March 4, '1958 F, w HOOPER 2,825,430

PAPER MACHINE HOOD Y Filed July 13, 1953 8 Sheets-Sheet 3 March 4, 1958 F. w. HooPER PAPER MACHINE Hoon 8 Sheets-Sheet 4 Filed July 13. 1953 March 4, 1958 F. w. HooPl-:R 2,825,43

PAPER MACHINE Hoon Filed July 15, 1953 8 Sheets-Sheet 5 i. Je

Mal'Ch 4 1958 F. w. HOOPER 2,25A3

'PAPER MACHINE Hoon Filed Jly 13. 1953 8 Sheets-Sheecl 6 March 4, 1958 F. w. HooPr-:R

PAPER MACHINE HOOD Filed July 13, 1955 8 Sheets-Sheet '7 1TH' BQ MalCh 4 F. w. HooPER .2,825,430

PAPER MACHINE HOOD Filed July 13, 1953 8 Sheets--Sheel'l Bl way ilnite States Patent PAPER MACHINE H001) Frederick Wiiliam Hooper, Montreah, Quebec, Canada,

assigner to Ross Engineering of Canada Limited, Montreal, Quebec, Canada, a corporationoffcanada.

Application July 13, 1953', Seral'No.. 367,627

12 Claims. (Cl. 1 89-1) The present invention relates to air processing systems and, more specifically, to enclosures or hood. structures utilized in such systems.

In certain industries, particularly inthe puip and paper industry, it is common practice to. provide some means of processingand recirculating the moist air which arisesfrom a drying machine or the like. In order to at least partially confine and evacuate.. such. air the usual procedure is to providesome. kind of air enclosureor hood over the top of the drying machine and alsoprovide some means' of exhausting the air so confined.

While. these. prior art structures are effective in preventing'excessive condensation and also at least partial control. of the air, these havel been designed'. so that they only partially hood the machine leaving thebottom por` tion open. The main purpose of providing a hoodor' enclosure over a machine. of this nature. is. to provide a means whereby the temperature and vapour content of theair. surrounding the machine may becontrolled more closely to. improve the operating. conditionsv for the machine.

One of the main reasons why prior art hoodV structures of this nature were not designed to totally enclose, for example, high speed paper drying machines, is that it is. necessary to provide for instant access to a machine of this type so a break, that may occur in the paper web, can be attended to before it piles up. Such breaks must be cleared as soon as possible so that the paper web can continue to run. through without having to stop the machine.A It is for this reason that in mostA paper mills the drying rolls are almost universally open-type machines so as.Y to enable the machine tender to watch the sheet and. handle breakslthat might occur on theudryingfrolls;

Accordingly, it was thought that if such machinesI were totally enclosed it would be impossiblev to have ready access to the drying. rolls and other operating portions as is required.

As is' well known, the presently accepted method for drying of apaper web on a high speed paper machine iscarried out bypassing the web over aseries of hot rolls which are heated internally by steam. This results in the formation of a large volume-of water vapour which is absorbed by warm air near'the machine and is` usually allowed to escape through openings in the roof, either by natural draft or by suction draft caused byany airmoving device drawing. the. hot air and vapour through a hood placed immediately over the machine and discharging the moisture-laden air outdoors.

As will be appreciated, a considerable volume of heated air is required to carry away such vapours. For example, a machine producing approximately a hundred. tons of newsprint every twenty-four hours requires. the evaporation of two hundred tous of water per day. An average of approximately one hundred thousand cubic feet. of air per minuteis necessary to carry away these. vapours. In accordance with the present invention, by.` the use of an overall: hood, the. energy in so. muclr'heated air. and

c EC@ warm vapour may be conserved and the necessary volume of air handled can be reduced'by at least fifty percent.

Further, the conditions of paper manufacture can` be improved by closer control of air conditions through conditioning of the air as confined by such a hood structure. The speed' of paper drying machines may be increased when hooded in accordance with the present invention by the speedier drying and the elimination of outside drafts etc., from the drying rolls.

The present hood structure is designed so that while affording complete protection to the machine on all sidesl also provides means whereby access can be had to either or both sides of the machine quickly and easily.

Accordingly, the invention comprises an overall hood structure adapted for use in enclosing a high-speed drying machine of the type having at least a major portion extending upwardly from a mill door. More specically, in a preferred construction the present hood structure consists of a self-supporting enclosure, mounted directly on the frame of the machine7 which includes a roof portion of a length substantially equal to the machine to be enclosed and a width slightly greater than the machine so as to extend beyond the machine at each side. Side walls are provided which are co-extensive in length with the roof portion and extend from the mill floor to the roof portioni End walls are provided which connect the roof and side walls at each end and include side portions extending from the mill floor to the roof and a central portion extending from the roof and terminating short of the mill floor to provide entry and exit passages for the ceding of material through the machine to be hooded.

In accordance with the present invention, each of the enclosures side walls includes a plurality of movable segments, and there are means provided for automatically moving the segments to provide access to the machine. Preferably, the side wall segments consist of a plurality of juxtaposed upper and lower panels which extend the length of the side wall. in the preferred construction, on one side wall the lower panels: are mounted for vertical sliding movement relative to the upper panels and the upper panels may be fixedV or mounted for horizontal sliding movement relative to each other. lnA the other sidewall either or both of the upper. and lower panelsare mounted for horizontal sliding movement relative toeach other.

The center portion of one. of the endV walls includes a lower portion also mounted for sliding movement in a vertical direction so that the' height of the entry passage to the machine at the enclosure' and may be varied to suit the particular machine over which the enclosure is mounted.

rIfhe enclosure structure itself includingV the roof, side walls and end wallsare preferably made vof panels of corrugated aluminum sheet mounted over a suitable steel framework. The roof is of two-ply insulated constru tion while the movable segments or slidingl doors are of opposed double-ply corrugated aluminum sheet construction so yas to provide the maximum in strength, insuiation, and rigidity while beingas light as'y possible.

The preferred means for raising and lowering the vertically slidably mounted side wall panels or doors comprises essentially a system of inter-connected shafts and pulleys which are driven by suitable electr-ic moto-rs, the individual doors being provided with rollers fitting into :and guided by vertical channels: or tracks secured'to the side Wallframe work;

In the preferred construction, theflower. side. wall. doors, `are arranged to be raised in several sections; for ein` ample, the; lifting mechanisms; for three adjacent. doors canrbe coupled and d-rivenrbyf afsinglef motor;

'Patented Mar. 4,"195skwork and the counterweight and ably, the controls for the driving motors `are such that eachV section can be raised individually or all the sec-V tions simultaneously.

.. DETAILED DESCRIPTION Y "Having" thusV generally described the VnatureV of ytheV invention, particular reference will be `made to the accompanying drawings showing by of illustration a pref ferred'construction in accordance with the invention or" an enclosure hood structure in combinationwith 'a highspeed paper drying machine, and in which:

Figure 1 is a diagrammatic View in perspective elevation of a complete hood structure inV accordance'wit'h the Y kinvention as it would appear in operative relationship over the'drying section of a high-speed paper machinelooking e from the wet end ofthe machine. i

Figure 2 is ra View in plan of the construction shown in Figurer'l.

VFigure 3 is a yiew in side elevation of the construction Vshown in Figure l Vwith all the doors shown in closed position. y Y Y Figure 4 is" a view in side elevation corresponding to Figure 3 of the opposite side of the machine showing ther'alternative arrangement of doors mounted for slid# ing horizontal movement. c

Figure 5 is a diagrammatic view of one end ofthe hood structure shown in Figure l,.which is positioned adjacent the fwet end ofthe drying machine.

Figure 6 is a diagrammatic view corresponding to Fig- Y Figure 9 is an enlarged sectional view of Figure 2Y along the line 9-9 to show fa typical transverse'section through the complete hood structure showing the relative position of the Adrying' rollersY and frame of the machine in broken lines. t

Figure l0 is a sectional view of Figure 9 along the line 10-10 to 'show a typical mounting arrangement be- Y tween a lsupporting'beam and the roof panels.

Figure 1l is an enlarged diagrammatic view, partially Vin section, along theline 1111 of Figure 3 to showin more detail the `construction of the supporting frame- V guiding arrangement for a vertically slidable door.

Figure 12 is a sectional view of Figure ll along the.Y line 12.-,-12 to show in more detail the guiding trackV and rollers for the vertically slidable doors. Y

Figure 13 Vis adiagrammatic view maiulyin section of ythe opposite side wall of the hood structure as .indicated along the line 13-13 of Figure 4.

Figure 14 is an enlarged Ydiagrammatic view vof a portion of avertica'lly slidable door showing the connection to the counte'rweight and to the door-lifting cable.

Figure` 15 is aV plan viewk of the construction shown in Figure 14, partially in section, along the line 15-15.

Figure 16 is a sectional view ofFigure 3 along the line 16--16 to show in enlarged detail the construction of the vertically slidable doors. y Y

Figure 17 is a Vdiagramrriatic-view of adjacent portions of two of the shaft arrangementsfon which the cable? winding pulleys are attached with a llexible coupling'disposedtbetween the adjacent shafts.

Y .Figure `18 is a diagrammatic view corresponding in loca- K frame members of .the machine-frame C so that the tion toY Figure 17, with the exception that no V.coupling arrangement is shown between the Iadjacent shaft por-VV tions. Y l Y Figure 19 is an enlarged diagrammatic view partially in section to show. atypical arrangement utilized to drive` the cable-winding pulleys for the vertical-lifting doors. f

Figure 20 isa diagrammatic View partially in section of Va cablewinding pulley and the upper portion of a vertically sliding door corresponding to the portion shown in Figure 14.

Figure 2l is a sectional view of the endV wall of the Yent Yclosure as shown in Figure 5 and along the line 2,1-721V to show in more Vdetail the central Vlifting panel adjacent the wet end of the'machine.V

Figure 22 is a cross sectional view of the end wallgof the Y hoodstructure adjacent the dry end of the machineV as shown in Figure V6Valong the line 22,-22.

Figure 23 is an enlarged cross sectional view ofraitypi-Y Y cal juncture between thexed end panels ofthe structure showninFigure 22.l Y Y Y Figure 24 is a view, in plan, of the chain and pulley ar-Y rangementrutilized' to raise the vertically sliding centre portion of the end wall constructiony shown in Figure'l. Y

along the Yline V24-24.

Figure 25,is a sectional viewot Figure 6 along therline V25---25 to illustrate the construction of the enclosure'end Y wall at the dry end in more detail..

Figure 26 is a diagrammatic'view in front'elevation orf' K a typical section of theV vertically lifting doors Von one 1on-` gitudinal side wall.

' Figure 27 is a section along Vthe line 27%27 of Figure y6V to show in more detail the internal construction of the ac-V cess door in the end wall.

With particularreference to Figures lthrough 6 and Y VFigure 9, a `preferred' hood construction inraccordance Y with thel present invention Vis .shown asV comprising essen- Y tially a roof portion 10,v longitudinal sidewall portionsY 12 and V1li,V andrend walls 16, 18, which are mounted over and supported by asteely framework connected to and ear tending from the upper frame of the machine enclosed;

'In the structure illustrated, the machine enclosedV is YVa high-speed paper drying kmachine having drying rollers B mounted on a supporting frame`Cf with the lower portions ofthe bottom dryer rolls D of the machinede` Y scending, below thermiil floor into the machine pit (notV shown). Y l Y The hood structureshown is'mounted Vdirectly on upper f portion of the machine extending above'the mill floorfA is `enclosedalong each side and Va major portion of both ends. TheV roof .portio'n 1Q is ofV substantially equal length to the machine and is greater in width so asto' ex-Y The sideY walls.12` 1 tend beyond the machine at each side. and 14 are substantially coextensive inlength with the roof 10 and extend Vfromthe mill oor A to the roof'at the Y eaves portions9. The end walls 16` and 18 connect the roof 10 and side walls 12 and 14 at each endrwiththeend wall 16.being disposed at the wet 'ori entry end of the machine and the end YWall 18 disposed at the dryf or dis# charge end of the machine. Y Each'of the endwalls V16, 18 include side panels at each side Vwhicliextend from the mill oor A to Vthe roof'lGfand each has .a central por-V tion which terminates short of the'mill flooiJA to pro-LV vide entry and discharge passages for the 'material feeding" 'y `In the construction shown the end wall Y 16 is provided withV a centre, panel v17 whichfis mounted l into the machine.

for sliding vertical movement relative to the upper station-Y ary portion 19 so that the height ofY the opening at Ythe Wet end of the Yhood can be adjusted'to suit-theV machine hooded. f Y Y* With particular reference'to Figure .9, showing in transverse cross-section the completerenclosure and particular-` iy the roof portion 10Y which is supported directly by steel beams 11 suppprted'from columns 13, resting onrrthe"V Y The columns 13 are securedto` therframe Vmembers C at'regularly`V upper frame member C of the machine.

spaced-apart intervals to suit the construction of the nia@V `chine which is being enclosed. SuitableV rafters 40, pref-x.`

erably of steel, are secured to the beams 11 at regularlyzVY spaced-apart relationship andthe roof structurel() is mounted on the rafter beams dil. In the preferred construction illustrated, the roof lil-is made up of a plurality of interconnected aluminum panels which are comprised of spaced-apartV sheets of aluminum having a packing 4l of insulating material, for example, Fiberglas, therebetween. These panels are. mounted directly over the rafters at? with a suitable insulation pad d2 therebetween at each joint to provide a complete insulated roof extending above the entire machine.

As indicated generally in Figure 2, suitable openings 42, 4d, 46 are provided in the roof 1l) and by means of airconditioning ducts F, the moisture-laden air can be withdrawn air supplied as is well known in the art.

ln the construction illustrated the longitudinal side walls l2 and 14 are made up of a plurality of segments or panels which arealigned in parallel upper and lower rows to form the enclosure walls. The lower segments or door panels 20 in the side wall 12 are mounted relative to the upper segments 22 which are xed, so as to be capable of vertical sliding movement towards and away from the mill oor A. The doors 2li illustrated are preferably arranged so that more than one door is raised simultaneously by single motor, as will be described later, and control means are provided whereby all the doors 2li extending along the length of the side wall i2 of the machine can be raised simultaneously. The longitudinal side wall lil extending along the opposite side of the machine also includes upper and lower segments or door panels 24, 26 which are arranged to be slidably movable in a horizontal direction.

The end wall i6 of the hood adjacent the wet end of the machine is also provided with a slidably movable centre portion 17, as previously described. Access doors 32, 33 are provided in each of the end walls 16, MS which are mounted for sliding vertical movement at one side of the centre opening of the respective end walls.

As will be appreciated, while the longitudinal side wall 12 shown consists of stationary upper doors 22 and lower vertically-slidable doors 2li, and the longitudinal wall 1.4 includes horizontally-slidable doors 2d, 25, this arrangement is illustrative only and the arrangement of the doors can be varied as desired, providing that on one side of the machine vertically slidable doors are provided giving ready access to the whole length of the machine so enclosed.

Vertzcally-sr'z'dable doors The vertically-slidable doors 2d which form the lower portion of the longitudinal side Wall l2 are each mounted between guide channels 7i? positioned in spaced-apart relationship on the upper half of the side wall. The guid-A ing members 7i) each constitutes a channel having outstanding anges 72 wherein guiding rollers 76 mounted at each side of the door panels 2t) are maintained in alignment during the travel of the doors. The rollers 76 are positioned adjacent the top portion of the doors only as is shown in detail in Figures 12 and 14, the lower portion of the door being guided through the contact of bordering channels Si which overlap the guiding channelsl 7) as shown in Figure 15.

The sliding doors or panels Zi) are each made up of juxtaposed sheets of corrugated aluminum which are joined centrally and connected at each side to the channel members Si. A typical cross-section of these doors is shown in Figure 16.

' 1n order that an adequate support be provided for the guiding and lifting means utilized in the operation of Vthe vertically sliding doors a supplementary framework 56 is provided on the side of the enclosure having the longitudinal side wall 12. rhe framework Sil extends outwardly from the roof portion lll to beyond the eaves portions 9 and then downwardly to a position approximately halfway to the mill floor A This frame is cross-braced at the lower end by spaced-apart longitudinal braces S2 which extend from the machine frame members C.l The bracing members 52 extend diagonally from the frame, C to a connection with the frame members. 54 which extend downwardly from the eaves portionsl 9` of the roof. The frame members 50, 54 and the diagonal braces 52 are disposed in spaced-apart relationship alongl thelength of the hood enclosure as will be described in more detail later.

The doors 20 are raised or lowered relative to the mill oor A through the medium of a plurality of spaced-apart winding drums Sil. rl`he drums are mounted in opposed pairs on shafts $4 each of which are journalled in suitable bearings 51 supported by the frame members dil. Driving gears. 82. are also connected to certain of the shafts Se so that driving motors 816 may, through a transmission 8S, and a chain drive 9.0, provide the necessary rotative movement to the shafts 84. The shafts 84 are disposed in axial alignment and in interconnected groups so that through the action of a single motor more than one pair of winding drums S0, and, consequently, more than one door panel 2) is raised; for example, as illustrated, three panels are so connectedin the present construction.

ln the case where more than one shaft 34-is to be driven by the same motor, for example three adjacent shafts as shown, the adjacent shaft ends 83 are coupledy by a flexible coupling as shown in Figure 17. In between each connected group of shafts, as is shownv ill Figure 18, there is no coupling between the adjacent shaft ends. It should also be noted that the drums 80a, 80h on each shaft 84 are left and right hand with respect to each door panel 2l), a connection being made from each drum to a fitting 23 provided at each side of each door 2t?. A flexible cable 81' extends about each respective drum surface and is connected by a suitable shackle S7 to the connecting member 23 at each side of each door 22.

In order to facilitate the lifting of the doors 2t) counterweights 10% are provided which are housed in suitable channel members 162 secured to the frame members 54 adjacent each lifting section. The counter-weights are connected by flexible cables HB3 to extensions 106 which extend above each side of the sliding doors 22 as is shown in Figure 14.

ln the preferred arrangement, each motor 85 is controlled from a master control panel indicated at H on Figure 1 so that each section of three doors can be lifted as required or alternatively all the doors 2li can be lifted simultaneously to provide access to the entire length of the machine.

The control panel is of the usual type having manually operated switches or buttons controlling the motors 86 and therefore is not illustrated in detail. lt is also contemplated that automatic switch operating means might be employed in cooperation with the control panel H for example, electronic web scanning means, or web supported rolls or feelers, whereby the doors 2@ would be raised automatically by the breaking of the web as it passes over the drying rollers.

On the opposite side of the enclosure, where the horizontally slidable doors 24, 25 are mounted to constitute the longitudinal side wall 14, bracing members 61 are also provided as extending from an internal catwalk K which extends the length of the machine. The bracing members 61 are disposed in spaced-apart relationship and serve to support the combined panels or doors 24, 26 against sideways motion. As will be appreciated, this structure is illustrative only and is peculiar to the arrangement shown. ln other and similar arrangements Where there might possibly be no catwalk similar bracing members would be provided from the machine frame to strengthen and support the side wall structure.

In order to maintain the maximum of sealing efficiency in the enclosure the lower edge of the doors 2li are provided with resilient sealing strips 21, see Figure 1l.

The doors 24, 26 are also provided with resilient rubbing or sealing strips 27a, 27h which extend between '."loor"A,seeFigure'lS. Y Y The construction 'of the doors 24, 26 is similar Vto that the adjacent offset doors, as shown in Figures 7 and 8.

Y' YAs thejlower 'doors 24 are offset or staggered it is possible'to provide an yaccess opening approximatelychalf between'the end walls In'the construction illustrated certain 'of the panels 26 are 'xed while others are mounted forV sliding` horizontal movement. The doors 24 in the' lower portion of thesside wall'14 are all'mounted forV horizontal sliding 'movement Y The [slidably mounted doors 26 and Y24 are provided with rollers 202 which'ride in channel members'204 suspended fromV the supporting Y' and 212'respectively thechannel sections 1212 being embedded in a concrete'curb M extending above the mill shown and described in connection with the doors -the main structural features being their'stre'ngth andglight-V vness due to the use .of Athe corrugated panels and alsothe between channel members 220; 221V as shown in Figure 27 and is provided with rollers 224 at each side to reduce friction. A suitable counterweight V222 is connected to the door 33 by means of a exible cable 226 passing overV pulley 2,28 so that the door canbe raised manually if required. A similar arrangement is providedat the end'wall 16 in connection with the door 32. Both the door 32 and the door 33 are provided with sealing strips along the lower marginal edge, see Figure 22. j

The vertically adjustable panelv 17 on the end wall 16 is also mounted between guiding channel members. As`

fthis panelis of greater area and is to be adjusted relative to the 'machine which is hooded there is provided a chain drive arrangement 230 which'operates a'shaft 232 mounted in suitableV bearings so as to extend across the Yend wall 16. `Sprocket gears 234 are mounted on the'shaft 232 and sprocket chains 236 extend abouttthe gears 234 to a connection withveach end of theV panel 17. With this arrangement, rotationof the chain drive 230 causes the gears` 2734 to wind up the chains 236 raising or lowering the'panel 17 depending on the direction of rotation. In'the structure illustrated suitable hand rails L Vand l access ladders N are provided for the purpose of adjustment and service. As previously recited, these are specio to the structure shown and other and similar hood structures might be constructed inaccor'dance with the invention without'these features.

Ifclaim: Y 'Y l. A hood Vsructure'for use in combination Ywith a high -speed paper drying machine, comprising a self-supporting enclosure having aY roof portion of sucient length toY cover Vsaid machine and of slightly greaterwidth to extend j beyond said machine at eachv side, endwalls disposed at each endof said roof portion eachhaving an open cen- Y tral section extending across a'major portion of Vthe Vwidth Y. Yframework uadjacent the eavesportions 95' The xed e panels 26 Yaresecured directly to a bracket member206 f extending along'rthek eaves portion 9. VThe lower portions Yof the doors Y26, 24 are' guided in channel `sections'210 cablesextending from each pair'of said drums to arcon` nection with the sides of each of said movable panels, and a driving motors connectedV Vto said shafts, said driving n fact that ina Vlike mannerV to the doors 20, 22, the doors 24, 26 areY hung from the roof structure ratherY than being vertical andY sliding movement intovk and out of overlapping relationshipwithY said upper panels between spaced apartV guiding members mounted on said'side wall upperv portion and lextending from adjacent the saidroof'portionto adjacent theY juncture between said upper` and lower Y panels, said ilower panelsvhaving bordering frame mem-V bers at Aeach side extending from,V adjacent thef lower marginaledges to beyondthe upper marginalfedges ofA said panels andlbeing slidably engaged withsaidV spaced-V j apart guiding members, panelmovingmeans mounted fon 'n said roof portionconnected to Veach of said lowerpanels, and control meansv connected torand adapted to Vactuate all orfpart of said panel movingmeans.I

2. A hood structure as claimedin Y J said means for moving said panels comprises, a plurality of vwinding drums mounted -in opposed spaced apart pairs on individual shafts, each ofrrsaid shaftsbeingmou'nted adjacent said roof portion Yfor-rotation above each of said vertically movable lower panels, Vsaid shaftsA beingY aligned axially along thelength of saidrenclosnre, exible motors being actuated through said controlling means.

byl coupling members extending from the adjacent ends of said shafts, and therefis a single driving motor connected to 'each coupled unit, Y

Y 4. A hood structure as'claimed in claimrl,V wherein one of saidV end walls includes a panel Vmounted'for slid-- ing movement relative torsaid centralopening whereby` the area of said opening may be adjusted relative Vtothe heightof said opening.

Y5. A- hood structure adaptedofor use in combination Y Ywith a high Vspeed, paper drying machine, comprising a; self-supporting enclosure having a roof portion of suf-v lcient length to cover said machine and of slightly greater width to extend beyond saidV machine at each side-,1end

walls disposed at each end `ot said roof portion, each ofY Y said end walls having an open central Ysection adapted to provide entry andrexitpassages for material processed on said machine, longitudinal-sideY wallsico-extensive. inf length with said roof portion fand connecting gsaidi end i walls at-each end, each of said side walls being made up Vof a plurality of juxtaposed panels disposedin two parallel.,V

rows forming upper and lower ^secotions extending the: n lengthk of said enclosure with the panels on the upper `and Y lower sections of one sidewall being mounted for hori- Yzontal sliding movement Yrelative to each other, andthe panels ofthe lower section oftheother side' wallbeing mounted Vforvertical :sliding movement :relative Ato the Vupper section by guiding members mounted kinrspaced y Y apart relationship between the upper panels'of said :sec-V ond side wall and terminating adjacent the juncture'of said upperY and lower panels,`.guicling channels Voneach side of 'each of/said lower panelsslidably'engaged with overlapping relationship with the; upper portions of said side wall, and control means adapted'to actuate all or part of said panel movingmeans.

v6. A hood structure forusein combination ra highY roof portion Yextending from said `roof portiontosaidfY Y,

mill floor, one of said side walls having'anupper portion and a lowerportion with said'lowerfportion made up of a pluralityof 'juxtaposed vertically slidably movable Y.

panels guided andrsupportedisolely from the upper porftion .of `said wall by spaced'apart panelV guiding membersY claim.Y l, wherein mounted on said wall upper portion and extending from adjacent the top of said wall upper portion to terminate adjacent the lower marginal edge of said wall upper portion, whereby said lower wall panels are adapted when raised to provide a clear, unobstructed passage from said mill oor to said side wall upper portion along the entire length of said machine, panel moving means mounted on said roof portion connected to each of said slidably movable panels and control means connected to said panel moving means.

7. A hood structure as claimed in claim 6, wherein said means for moving said vertically movable panels comprises a plurality of winding drums mounted in opposed spaced apart pairs on individual shafts, each of said shafts being mounted for rotation above each of said movable panels adjacent said roof portion, said shafts being aligned axially along the length of said enclosure, flexible cables extending from each pair of said drums to a connection with the sides of each of said movable panels, and driving motors connected Ato said shafts, said driving motors being connected to said controlling means.

8. A hood structure as claimed in claim 6 including end walls each having a central open portion extending across a major portion of the width of said enclosure, one of said end walls having a panel mounted for vertical and sliding movement relative to said central opening whereby the area of said opening may be adjusted relative to the height of said opening.

9. A hood structure for use in enclosing a high speed paper machine of the type having at least a portion extending upward from the mill oor, said hood structure comprising a self-supporting structure mounted directly on the frame of said machine and including a roof portion of a length substantially equal to the machine to be enclosed and a width slightly greater than said machine so as to extend beyond said machine at each side, said enclosure including side walls co-extensive in length with said roof portion and extending from said mill oor to said roof portion, and end walls connecting said roof and side walls at each end and having side portions extending from said mill floor to said roof and a central portion extending across a major portion of the width of said enclosure from said roof and terminating short of said mill oor to provide entry and exit passages for; the feeding of material through said machine, one of said enclosure side walls being made up of a plurality of juxtaposed upper and lower panels extending the length of said side wall, a plurality of guiding members lixedly mounted in spaced relationship along the length of said upper panels, said guiding members extending from adjacent the roof of said enclosure to terminate at the lower margin of said upper panels, said lower panels each being provided with bordering guiding channels at each side slidably engaged with said spaced guiding members whereby they are mounted for vertical sliding movement relative to said upper panels, and means for moving said lower panels to provide unobstructed access to said machine along the length of said side wall and between said mill oor and the lower marginal edges of said panels.

10. A hood structure as claimed in claim 9 wherein the means for moving said panels comprises a plurality of winding drums mounted in opposed spaced apart pairs on individual shafts, each of said shafts being mounted for rotation above each of said movable panels adjacent said roof portion, said shafts being aligned axially along the length of said enclosure, exible cables extending from each pair of said drums to a connection with the sides of each of said movable panels, driving motors connected to said shafts, and control means adapted to selectively actuate said driving motors.

11. A hood structure as claimed in claim 9, wherein the other of said side walls comprises a plurality of juxtaposed upper and lower panels extending the length of said side walls, and said upper and lower panels are mounted for horizontal sliding movement relative to each other, said panels each being arranged in staggered relationship to each adjacent panel.

12. A hood structure as claimed in claim 9, wherein one of said end walls includes a panel mounted for sliding vertical movement relative to said central opening whereby the area of said opening may be adjusted relative to the height of said opening.

References Cited in the le of this patent UNITED STATES PATENTS 757,179 Cross Apr. 12, 1904 1,199,012 Lamer Sept. 19, 1916 1,229,478 Kramer June 12, 1917 1,283,836 McCloud Nov. 5, 1918 1,970,222 Byrne Aug. 14, 1934 2,184,774 Browning Dec. 26, 1939 2,466,913 Rogers Apr. 12, 1949 FOREIGN PATENTS 12,304 Great Britain Sept. 10, 1887 

